SC91415AP SILAN [Silan Microelectronics Joint-stock], SC91415AP Datasheet - Page 11

• Manufacturer Part Number: SC91415AP
• Description: TONE/PULSE SWITCHABLE DIALER WITH LCD INTERFACE AND DUAL-TONE MELODY
• Manufacturer: SILAN [Silan Microelectronics Joint-stock]

D) Handfree (HF) function
The handfree function is designed to support on-hook dialing and loudspeaker application which can be turn “on” or
“off” with falling edge signal from
Otherwise the HFO pin stays “low” level. One of the following operations can turn off Handfree function (HFO pin
return to “Low”).
* On-off hook once.
* Trigger
* Turn on Hold (HD) function. (HDO pin switched to “High”)
E) Hold (HD) function
The Hold function is designed to stop conversation temporarily. In off-hook state (or HF function is turned on), to
press HD key on the keyboard, the Hold function can be turned “on” (HDO pin switched to “High”). One of the
following operations can turn off Hold function (HDO pin switched to “Low”).
* On-off hook once.
* To press HD key over 280 ms.
* Turn on Handfree (HF) function. (HFO pin switched to “High”)
Special Note
A 300 ms delay time (Tdly) at the first Off-Hook or turn on Handfree that is a special designed to avoid a rapid key
entry (dummy number ) in this time duration ,and a long distance call number follows. For example,
Off-Hook , “3” ,.................... , “0” ,1,2,3......
The dummy number “3” is not detected by the centered office or PABX ,but the following numbers “0” ,1,2,3... long
distance call can be dialed out normally since the leading number “3” is not the Lock-number defined in SC91415
series. To prevent the unavoidable long distance call, then SC91415 inhibits the key entry during Tdly.
F) Operating
flow chart
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
HFI
Dummy key
Silan
Semiconductors
pin with falling edge signal.
HD
HD
Handfree State
Holdline State
Lock number key
On-hook
On-hook
HFI
4
6
HF
pin. During handfree function is executed, the HFO pin is switched to “high”.
HKS=Hi
HF
HF
Handfree State
On-hook State
HKS=Lo
Off-hook
HKS=Lo
HKS=Hi
11
1
3
HD
HF
HKS=Hi
HF
HF
HKS=Lo
Off-hook State
Holdline State
Off-hook
HD
2
5
HD
Rev: 2.0
Note :
HF= Handfree,
HD = Hold
2001-11-13